This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cystic Fibrosis is a disorder that is characterized by specific gastrointestinal, endocrine and respiratory symptoms. The latter is associated with recurrent endobronchial pseudomonas infections that is difficult to manage systemically and patients ultimately suffer from compromised pulmonary function that reduces the time of overall survival. A recent breakthrough in pulmonary inhalation therapy with a jet nebulizer delivering the antibiotic tobramycin has dramatically affected the recurrence rate of Pseudomonas Aeruginosa infection and has result in improved pulmonary function. As with all antibiotic therapy, a subset of patients have developed a tobramycin resistant strain of Pseudomonas that makes it difficult to treat these patients on a continuous basis. More recently, studies with the fluoroquinolone drug Ciprofloxacin has shown to be quite effective in reducing the virulence of Pseudomonas in both animal models and in Phase I studies in human and has been developed for inhalation therapy as a more potent alternative to tobramycin for managing chronic Pseudomonas infections in CF patients.